/* button press also turns LED off */
digraph {
  pad=0.5; bgcolor="lightgrey"; nodesep=1;
  node [shape="box"; style="filled";  fillcolor="cyan"];
  edge [labelfontsize=10; minlen=2; labeldistance=3 ];
  RTB_IDLE -> RTB_ON [taillabel="EVT_BUTTON                      "];
  RTB_ON -> RTB_IDLE [taillabel="                EVT_TICK \n               && counter==0"];
  RTB_ON -> RTB_IDLE [taillabel="                EVT_BUTTON";];
}